JP2020532647A - Chemical vapor deposition process for forming a silicon oxide coating - Google Patents

Abstract

The chemical vapor deposition process for forming a silicon oxide coating involves providing a moving glass substrate. A gas mixture is formed containing a silane compound, a first oxygen-containing molecule, a radical scavenger, and at least one of a phosphorus-containing compound and a boron-containing compound. The gas mixture is oriented towards and along the glass substrate. The gas mixture is reacted on the glass substrate to form a silicon oxide coating on the glass substrate at a deposition rate of 150 nm * m / min or higher.

Description

Cross-reference to related applications This application is granted Article 62 / 552,713 under Article 119 of the US Patent Act, claiming the interests of a US provisional patent application filed on August 31, 2017. The entire disclosure is incorporated herein by reference.

The present invention generally relates to the process of forming a silicon oxide coating. Specifically, the present invention relates to a chemical vapor deposition (CVD) process for forming a silicon oxide coating on a glass substrate. The present invention also relates to coated glass articles having a silicon oxide coating formed on the glass articles.

Silicon oxide coatings are known to deposit on glass substrates. However, the known process for the formation of silicon oxide coatings is limited by the efficiency of the deposition process and / or the powder formation (pre-reaction) of reactive elements. Therefore, it is desired to devise an improved process for forming a silicon oxide coating on a glass substrate.

Embodiments of the chemical vapor deposition process for forming a silicon oxide coating are described below. In one embodiment, the chemical vapor deposition process for forming a silicon oxide coating comprises providing a moving glass substrate. A gas mixture is formed containing a silane compound, a first oxygen-containing molecule, a radical scavenger, and at least one of a phosphorus-containing compound and a boron-containing compound. The gas mixture is oriented towards and along the glass substrate. The gas mixture is reacted on the glass substrate to form a silicon oxide coating on the glass substrate at a deposition rate of 150 nm * m / min or higher.

In some embodiments, the glass substrate is a glass ribbon in the float glass manufacturing process.

In another embodiment, the silicon oxide coating is formed on the deposited surface of a glass substrate that is essentially at atmospheric pressure.

In yet another embodiment, when the silicon oxide coating is formed on the glass substrate, the glass substrate is at a temperature of 1100 ° F (593 ° C) to 1400 ° F (760 ° C).

In one embodiment, the gas mixture comprises a phosphorus-containing compound.

In some embodiments, the phosphorus-containing compound is an ester.

In one embodiment, the phosphorus-containing compound is triethyl phosphate.

In some embodiments, the gas mixture comprises less than 0.7 mol% of the phosphorus-containing compound.

Preferably, the ratio of the phosphorus-containing compound to the silane compound in the gas mixture is 1: 100 or more.

Unless otherwise specified, all ratios described in this application are expressed in mol%.

In some embodiments, the ratio of phosphorus-containing compound to silane compound is 1: 100 to 1: 1.

In some embodiments, the gas mixture comprises a boron-containing compound.

In some embodiments, the boron-containing compound is an ester.

In one embodiment, the boron-containing compound is triethylborane.

In some embodiments, the ratio of boron-containing compound to silane compound in the gas mixture is 1:10 or greater.

In some embodiments, the gas mixture comprises a phosphorus-containing compound and a boron-containing compound.

In some embodiments, the ratio of boron-containing compound to phosphorus-containing compound in the gas mixture is 1: 1 or greater.

In some embodiments, the ratio of boron-containing compound to phosphorus-containing compound in the gas mixture is 2: 1 or greater.

Preferably, the silane compound is monosilane, the first oxygen-containing molecule is molecular oxygen, and the radical scavenger is ethylene.

In some embodiments, the gas mixture also comprises a second oxygen-containing molecule. In this embodiment, the first oxygen-containing molecule is molecular oxygen and the second oxygen-containing molecule is water vapor.

In some embodiments, the gaseous mixture contains more water vapor than molecular oxygen.

In other embodiments, the gas mixture comprises 50% or more water vapor based on mol%.

Preferably, the gas mixture comprises a phosphorus-containing compound, a boron-containing compound, and a second oxygen-containing molecule.

In some embodiments, a coating device is provided in which a gas is fed through the coating device before the silicon oxide coating is formed on the glass substrate.

In some embodiments, the silicon oxide coating is formed on a coating previously formed on the glass substrate.

Preferably, the silicon oxide coating is pyrolytic.

Preferably, the deposition rate is 175 nm * m / min or higher.

In some embodiments, the deposition rate is 200 nm * m / min or higher.

The above as well as other advantages of the process will be readily apparent to those skilled in the art from the embodiments for carrying out the invention below, when considered in the light of the accompanying drawings, the drawings being floated according to the embodiments of the present invention. It is the schematic of the vertical cross section of the equipment for carrying out a glass manufacturing process.
The drawing is a schematic vertical cross section of a facility for carrying out a float glass manufacturing process according to an embodiment of the present invention.

It should be understood that the present invention, on the contrary, can envision a variety of alternative orientations and process sequences, unless explicitly specified. It should also be understood that the particular articles, devices, and processes described herein are merely exemplary embodiments of the concepts of the invention. Therefore, certain dimensions, orientations, or other physical properties associated with the disclosed embodiments should not be considered limiting unless otherwise specified. Also, although this may not be the case, similar elements in the various embodiments described within this section of the application may generally be referred to by similar reference numbers.

In one embodiment, a CVD process (hereinafter, also referred to as “CVD process”) for forming a silicon oxide coating is provided.

The CVD process is described in the context of coated glass articles. In certain embodiments, the coated glass article can be applied in the manufacture of solar cells. However, the coated glass articles described herein are not limited to solar cell applications. For example, coated glass articles can be used in architectural glass, electronics, and / or have automotive and aerospace applications.

The silicon oxide coating contains silicon and oxygen. In certain embodiments, the silicon oxide coating may contain phosphorus. In some of these embodiments, the silicon oxide coating may consist essentially of silicon, oxygen, and phosphorus. In other embodiments, the silicon oxide coating may contain boron. In some of these embodiments, the silicon oxide coating may consist essentially of silicon, oxygen, and boron. In yet other embodiments, the silicon oxide coating may include phosphorus and boron. In some of these embodiments, the silicon oxide coating may consist essentially of silicon, oxygen, phosphorus, and boron. The silicon oxide coating may also contain trace amounts of one or more additional components, such as carbon. As used herein, the phrase "trace" is the amount of constituents of a silicon oxide coating that cannot always be quantitatively determined due to its microscopicity.

A feature of the CVD process is the ability to form a silicon oxide coating at a commercially viable deposition rate. In addition, the advantage of the CVD process is that it is more efficient than the known process for forming silicon oxide coatings. Therefore, a commercially viable deposition rate can be achieved using less silicon-containing precursor compounds than known processes, which reduces the cost of forming a silicon oxide coating. For example, utilizing a CVD process, the silicon oxide coating can be formed at a dynamic deposition rate of 150 nanometers * m / min (nm * m / min) or higher. Such deposition rates can be achieved by utilizing less silane compounds than are required in known processes to achieve the same dynamic deposition rates. Moreover, in certain embodiments, the CVD process allows the formation of a silicon oxide coating at a deposition rate faster than the deposition rate of known processes. For example, utilizing a CVD process, the silicon oxide coating can be formed with a dynamic deposition rate of 175 nm * m / min or higher. Such deposition rates can be achieved utilizing approximately the same amount of silane compounds used in the comparison process in order to achieve lower dynamic deposition rates. In some embodiments, the silicon oxide coating can be formed even at dynamic deposition rates of 200 nm * m / min and above.

The silicon oxide coating is formed on the substrate. It should be understood that the silicon oxide coating can be formed directly on the substrate or on the coating previously deposited on the substrate. Preferably, the silicon oxide coating is formed on the glass substrate. In one embodiment, the glass substrate has a deposited surface on which a silicon oxide coating is formed.

The CVD process can be performed in conjunction with the manufacture of the glass substrate. In one embodiment, the glass substrate can be formed utilizing a well-known float glass manufacturing process. An example of a float glass manufacturing process is shown in the figure. In this embodiment, the glass substrate can also be referred to as a glass ribbon. However, it should be understood that the CVD process can be utilized separately from the float glass manufacturing process or well after the formation and cutting of the glass ribbon.

In certain embodiments, the CVD process is a dynamic deposition process. In these embodiments, the glass substrate is moving during the formation of the silicon oxide coating. Preferably, the glass substrate travels at a predetermined speed, for example in excess of 3.175 m / min (125 inch / min), while the silicon oxide coating is being formed. In one embodiment, the glass substrate is moving at a speed of 3.175 m / min (125 inch / min) to 12.7 m / min (600 inch / min) while the silicon oxide coating is being formed.

In certain embodiments, the glass substrate is heated. In one embodiment, when the silicon oxide coating is formed, the temperature of the glass substrate is about 1100 ° F (593 ° C) or higher. In another embodiment, when the silicon oxide coating is formed on the glass substrate, the temperature of the glass substrate is 1100 ° F (593 ° C) to 1400 ° F (760 ° C).

Preferably, the silicon oxide coating is deposited on the deposited surface of the glass substrate while the surface is essentially at atmospheric pressure. In this embodiment, the CVD process is an atmospheric CVD (APCVD) process. However, the CVD process is not limited to the APCVD process, and in other embodiments, the silicon oxide coating can be formed under low pressure conditions.

The glass substrate is not limited to a specific thickness. Further, the glass substrate can be a conventional glass composition known in the art. In one embodiment, the glass substrate is soda lime silica glass. In some embodiments, the substrate can be part of a float glass ribbon. However, the CVD process is not limited to soda lime silica glass substrates, and in other embodiments the glass substrate can be borosilicate or aluminosilicate glass.

Also, the transparency or absorption properties of the glass substrate can vary between embodiments. For example, in certain embodiments, it may be preferable to utilize a glass substrate with a low iron content that allows the glass substrate to exhibit high visible light transmission. In some embodiments, the glass substrate may contain less than 0.15% by weight Fe ₂ O ₃ (total iron). As used herein, the phrase "total iron" refers to the total weight of iron oxide (FeO + Fe ₂ O ₃ ) contained in glass. More preferably, the glass substrate contains Fe ₂ O ₃ (total iron) of 0.1% by weight or less, and even more preferably 0.02% by weight or less of Fe ₂ O ₃ (total iron). In one embodiment, the glass substrate contains 0.012% by weight Fe ₂ O ₃ (total iron). In these embodiments, the glass substrate can exhibit a total visible light transmittance of 91% or more in the CIELAB color scale system (light source C, 10 degree observation device). In addition, the color of the glass substrate can vary between embodiments of the CVD process. In one embodiment, the glass substrate can be substantially transparent. In other embodiments, the glass substrate can be tinted or colored.

Silicon oxide coatings are a source of silane compounds, one or more sources of one or more oxygen-containing molecules, sources of phosphorus-containing compounds, sources of boron-containing compounds, and sources of radical scavengers. It can be deposited by providing one or more of them. In one embodiment, the source of oxygen-containing molecules can be a source of water. A separate supply line can extend from the source of the reactant (precursor) molecule. As used herein, the terms "reactant molecule" and "precursor molecule" refer to any or all of the silane compounds: one or more oxygen-containing molecules, radical scavengers, phosphorus-containing compounds, and boron. It may be used interchangeably to refer to a contained compound and / or to describe its various embodiments disclosed herein. Preferably, the source of precursor molecules is provided at a location outside the float bathroom.

Preferably, the silicon oxide coating is deposited by forming a gas mixture. Precursor molecules suitable for use in gas mixtures are preferably suitable for use in CVD processes. Such molecules can be liquid or solid at some point, but they are volatile enough to vaporize for use in gas mixtures. In certain embodiments, the gas mixture contains precursor molecules that are essentially suitable for forming a silicon oxide coating at atmospheric pressure. Once in the gaseous state, the precursor molecules may be included in the gas stream and may be utilized to form a silicon oxide coating.

For any particular combination of gas precursor molecules, the optimum concentration and flow rate to achieve a particular deposition rate and coating thickness can vary. However, in order to form a silicon oxide coating, the gas mixture preferably contains a silane compound, one or more oxygen-containing molecules, a radical scavenger, and at least one of a phosphorus-containing compound and a boron-containing compound. In one embodiment, the gas mixture comprises a phosphorus-containing compound. In another embodiment, the gas mixture comprises a boron-containing compound. In a further embodiment, the gas mixture may comprise a phosphorus-containing compound and a boron-containing compound.

In one embodiment, the silane compound is monosilane (SiH ₄ ). However, other silane compounds are suitable for use in the deposition of silicon oxide coatings. For example, disilane (Si 2 _{H 6)} is another silane compound may be utilized to deposit the silicon oxide coating.

In some embodiments, one or more of the silane compound, the radical scavenger, the phosphorus-containing compound, and the boron-containing compound may contain one or more oxygen elements. However, it is understood that the phrase "one or more oxygen-containing molecules" refers to one or more molecules contained in a gas mixture that is separate from silane compounds, radical scavengers, phosphorus-containing compounds, and boron-containing compounds. I want to be. The one or more oxygen-containing molecules include a first oxygen-containing molecule. In one embodiment, the first oxygen-containing molecule is molecular oxygen (O ₂ ), which can be provided as part of a gaseous composition such as air or in a substantially purified form. In another embodiment, the first oxygen-containing molecule is water (H 2 _O) vapor, it may be provided as a vapor. In certain embodiments, the one or more oxygen-containing molecules comprises two oxygen-containing molecules. In one such embodiment, the gas mixture comprises a first oxygen-containing molecule and a second oxygen-containing molecule. In this embodiment, the first oxygen-containing molecule may be molecular oxygen, and the second oxygen-containing molecule may be water vapor or vice versa.

In some embodiments, the gaseous mixture may contain more water vapor than molecular oxygen. For example, in some embodiments, the ratio of molecular oxygen to water vapor in the gas mixture can be 1:20 or greater. In one such embodiment, the ratio of molecular oxygen to water vapor in the gas mixture is 1:20 to 1: 1. In other embodiments, the ratio of molecular oxygen to water vapor in the gas mixture can be 1:15 or greater. In one such embodiment, the ratio of molecular oxygen to water vapor in the gas mixture is 1: 15 to 1: 1. Moreover, in some embodiments, the gas mixture may contain 50% or more water vapor, which can be based on mol percent (mol%). In some of these embodiments, the gas mixture may contain 50-90% water vapor. In other embodiments, the gas mixture may contain 50-80% water vapor.

The silane compound may be pyrophoric, and when one or more oxygen-containing molecules are added to the gas mixture containing the pyrophoric silane compound, a silicon oxide coating such as silica (SiO ₂ ) is produced. obtain. However, coatings are formed at unacceptably high rates and explosive reactions can occur. Known methods of preventing such reactions result in coating deposition at very low commercially impractical rates. Known methods also limit the amount of silane and oxygen that can be contained in the gas mixture. This is because if the concentration is too high, a vapor phase reaction of the elements will occur and no coating will be formed. Therefore, the gas mixture preferably contains a radical scavenger.

Due to the presence of the radical scavenger, the silane compound can be mixed with one or more oxygen-containing molecules without ignition and premature reaction at operating temperature. Radical scavengers further provide control of reaction kinetics above, near, and / or above the glass substrate, further enabling optimization of reaction kinetics. In one embodiment, the radical scavenger is a hydrocarbon gas. Preferably, the hydrocarbon gas is ethylene (C ₂ H ₄ ) or propylene (C ₃ H ₆ ).

In one embodiment, the phosphorus-containing compound is an organic phosphorus-containing compound. Esters are organophosphorus-containing compounds that are preferred for use in gas mixtures. Thus, in one embodiment, the phosphorus-containing compound is an ester. For example, in one embodiment, the phosphorus-containing compound is triethyl phosphate (TEP). In another embodiment, the phosphorus-containing compound can be triethyl phosphate (TEPO). However, other phosphorus-containing compounds may be suitable for use in gas mixtures.

The advantage of utilizing a phosphorus-containing compound to form a silicon oxide coating, as in the above embodiment, can be realized by selecting the ratio of the phosphorus-containing compound to the silane compound in the gas mixture. For example, in one embodiment, the ratio of the phosphorus-containing compound to the silane compound in the gas mixture is 1: 100 or more. In certain embodiments, the ratio of phosphorus-containing compounds to silane compounds in the gas mixture is 1: 100 to 1: 1. For example, the ratio of phosphorus-containing compound to silane compound in the gas mixture can be 1:50. In some embodiments, the ratio of phosphorus-containing compounds to silane compounds in the gas mixture is 1:50 to 1: 1. In some embodiments, it may be desirable to limit the amount of phosphorus-containing compounds in the gas mixture. In one such embodiment, the mol% of the phosphorus-containing compound in the gas mixture can be less than 0.7. For example, the gas mixture may contain up to 0.6 mol% of phosphorus-containing compounds. If the gas mixture contains a phosphorus-containing compound, the silicon oxide coating may contain trace amounts or more of phosphorus.

When the gas mixture contains a boron-containing compound, the boron-containing compound is preferably an organic boron-containing compound. Thus, in one embodiment, the boron-containing compound is an ester. In one such embodiment, the boron-containing compound is triethylborane (TEB). However, other boron-containing compounds may be suitable for use in gas mixtures.

The advantage of utilizing a boron-containing compound to form a silicon oxide coating, as in the above embodiment, can be realized by selecting the ratio of the boron-containing compound to the silane compound in the gas mixture. For example, in one embodiment, the ratio of the boron-containing compound to the silane compound in the gas mixture is 1:10 or more. In one embodiment, the ratio of boron-containing compound to silane compound in the gas mixture is 1: 10 to 1: 1. In another embodiment, the ratio of boron-containing compound to silane compound in the gas mixture is 1: 5 to 1: 1. In yet another embodiment, the ratio of boron-containing compound to silane compound in the gas mixture is 1: 2 to 1: 1.

In certain embodiments where the gas mixture comprises a phosphorus-containing compound and a boron-containing compound, it may be preferable that the gas mixture contains more boron-containing compounds than the phosphorus-containing compound. However, in other embodiments, it may be preferable to have equal amounts of boron-containing and phosphorus-containing compounds in the gas mixture. In yet another embodiment, it may be preferable that the gas mixture contains more phosphorus-containing compounds than boron-containing compounds. In the above embodiments, the amounts of boron-containing and phosphorus-containing compounds in the gas mixture can be on a molar% basis.

The gas mixture may also contain one or more inert gases that are utilized as carrier gases or diluent gases. Suitable inert gases include nitrogen (N ₂ ), helium (He), and mixtures thereof. Therefore, one or more sources of inert gas may be provided from which a separate supply line can extend.

The precursor molecules are mixed to form a gas mixture. As mentioned above, the silane compound can be mixed with one or more oxygen-containing molecules due to the presence of the radical scavenger without undergoing ignition and premature reaction. When provided, the phosphorus-containing compound is also preferably mixed with a silane compound, oxygen-containing molecules (s), and a radical scavenger to form a gas mixture. Also, when provided, the boron-containing compound is also preferably mixed with a silane compound, oxygen-containing molecules (s), and a radical scavenger to form a gas mixture. In certain embodiments, the boron-containing compound is mixed with a silane compound, an oxygen-containing molecule (s), a radical scavenger, and a phosphorus-containing compound to form a gas mixture.

As mentioned above, in some embodiments, it may be preferable that the gas mixture comprises a boron-containing compound and a phosphorus-containing compound. By having both the boron-containing compound and the phosphorus-containing compound in the gas mixture, the silicon oxide coating is more than the deposition rate of the silicon oxide coating when only one of the boron-containing compound and the phosphorus-containing compound is contained in the gas mixture. It can be formed at a high deposition rate. In embodiments where the gas mixture comprises a boron-containing compound and a phosphorus-containing compound, the ratio of the boron-containing compound to the phosphorus-containing compound in the gas mixture can be 1: 1 or greater. In some of these embodiments, it may be preferable to have more boron-containing compounds in the gas mixture than phosphorus-containing compounds. In one such embodiment, the ratio of boron-containing compound to phosphorus-containing compound in the gas mixture can be 2: 1 or greater.

In certain embodiments, coating devices may be provided. Preferably, the gas mixture is fed through a coating device before the silicon oxide coating is formed on the glass substrate. The gas mixture can be expelled from the coating apparatus utilizing one or more gas distributor beams. Preferably, the gas mixture is formed before being fed through the coating device. For example, precursor molecules can be mixed in a feed line connected to the inlet of the coating device. In other embodiments, the gas mixture can be formed within the coating device.

The advantages of the CVD process described herein are a significant increase in deposition rate and a reduction in the amount of pre-reaction / powder formation that occurs in the case of silicon oxide coating formation. Therefore, the CVD process can be operated with much longer run lengths than traditional processes. Depending on the required silicon oxide coating thickness, the coating formed by the CVD process can be deposited by forming multiple silicon oxide coating layers in succession. However, another advantage of the CVD process is that, depending on the desired thickness, only a single coating device may be required to form the silicon oxide coating.

Preferably, the coating device extends across the glass substrate and is provided above it at a predetermined distance. The coating device is preferably positioned at at least one predetermined position. If the CVD process is utilized in conjunction with the float glass manufacturing process, the coating equipment is preferably provided within its float bath section. However, the coating device may be provided in the glass annealing furnace and / or in the gap between the float bath and the annealing furnace.

The gas mixture is oriented towards and along the glass substrate. Utilization of the coating device helps to direct the gas mixture towards and along the glass substrate. Preferably, the gas mixture is oriented in a laminar flow towards and along the glass substrate.

The gas mixture reacts on or near the glass substrate to form a silicon oxide coating on the glass substrate. Utilization of the above gas mixture embodiments results in the deposition of a high quality coating layer on the glass substrate with virtually no defects. Also, the silicon oxide coating can exhibit excellent coating thickness uniformity.

In some embodiments, the silicon oxide coating is pyrolytic. As used herein, the term "pyrolytic" can refer to a coating that chemically bonds to a glass substrate. In some embodiments, the silicon oxide coating has a refractive index of less than 1.6. Preferably, the silicon oxide coating has a refractive index of 1.2-1.6. More preferably, the silicon oxide coating has a refractive index of 1.2 to 1.5. The above refractive index values are reported as average values over the 400-780 nm range of the electromagnetic spectrum.

In some embodiments, the gas mixture comprises a silane compound, a first oxygen-containing molecule, and a radical scavenger. Preferably, the silane compound is monosilane, the first oxygen-containing molecule is molecular oxygen, and the radical scavenger is ethylene. It has been found that when a phosphorus-containing compound or a boron-containing compound is added to such a gas mixture, a silicon oxide coating can be formed during the movement of the glass substrate at a deposition rate of 150 nm * m / min or higher. In some embodiments, the silicon oxide coating can be formed at a deposition rate of 175 nm * m / min or higher during the movement of the glass substrate. It was further found that further increases in the deposition rate of the silicon oxide coating could be achieved if the gas mixture contained a second oxygen-containing molecule, such as water vapor, and a phosphorus-containing or boron-containing compound. For example, the silicon oxide coating can be formed at a deposition rate of 200 nm * m / min or higher during the movement of the glass substrate. In some embodiments, it may be preferable that the gas mixture comprises a secondary oxygen-containing molecule, a phosphorus-containing compound, and a boron-containing compound.

In some of the above embodiments, the silicon oxide coating may include silicon dioxide (SiO ₂ ) and phosphorus. In other embodiments, the silicon oxide coating may include silicon dioxide and boron. It should be noted that, in general, increasing the amount of boron-containing compounds in the gas mixture increases the amount of boron in the silicon oxide coating. In yet other embodiments, the silicon oxide coating may include silicon dioxide, boron, and phosphorus.

The silicon oxide coating can be formed on one or more previously deposited coatings. For example, the silicon oxide coating can be formed on the previously deposited tin oxide coating formed on the deposited surface of the glass substrate. In this embodiment, the tin oxide coating on which the silicon oxide coating is deposited can be doped with fluorine or deposited directly on the glass substrate. The silicon oxide coating can be formed directly on the tin oxide coating. Alternatively, the silicon oxide coating can be formed directly on the glass substrate. In this position, the silicon oxide coating can act as a sodium diffusion barrier between the glass substrate and any coating formed on the silicon oxide coating. This can be especially beneficial if the glass substrate is soda lime silica glass.

As mentioned above, the silicon oxide coating can be formed in conjunction with the production of the glass substrate in a well-known float glass production process. The float glass manufacturing process is typically performed utilizing a float glass facility such as the facility 30 shown in the figure. However, it should be understood that the float glass equipment 30 described herein is merely an example of such equipment.

As shown in the figure, the float glass facility 30 may include a groove section 32 in which the molten glass 34 is delivered from the melting furnace to the float bath section 36 where the glass substrate is formed. In this embodiment, the glass substrate is referred to as the glass ribbon 38. The glass ribbon 38 is a preferred substrate on which a silicon oxide coating is formed. However, it should be understood that the glass substrate is not limited to being a glass ribbon.

The glass ribbon 38 proceeds from the bath section 36 through the adjacent glass annealing furnace 40 and cooling section 42. The float bath section 36 includes a bottom section 44 containing a bath of molten tin 46, a top 48, opposing side walls (not shown), and end walls 50, 52. The top 48, side walls, and end walls 50, 52 all define an enclosure 54 in which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin 46.

During the operation, the molten glass 34 flows along the groove 32 below the adjustment twill 56 and flows downward on the surface of the tin bath 46 in a controlled amount. On the molten tin surface, the molten glass 34 spreads laterally under the influence of gravity, surface tension, and certain mechanical influences and travels across the tin bath 46 to form the glass ribbon 38. The glass ribbon 38 is removed from the bath section 36 on the lift-out roll 58 and then transported through the glass annealing furnace 40 and the cooling section 42 on the alignment roll. The deposition of the silicon oxide coating is preferably carried out in the float bath section 36, but further along the glass production line, for example in the gap 60 between the float bath 36 and the glass annealing furnace 40, or in the glass annealing furnace 40. Within, it is possible to carry out deposition.

As shown in the figure, the coating device 62 is shown within the float bath section 36. The silicon oxide coating can be formed using the coating device 62. In this embodiment, the silicon oxide coating can be formed directly on the glass substrate. In certain embodiments, the silicon oxide coating can be formed on one or more coatings previously formed on the glass ribbon 38. Each of these coatings can be formed utilizing a separate coating device. For example, in one embodiment, coating devices 62, 64 can be utilized to deposit a coating layer containing non-doped tin oxide. In this embodiment, the silicon oxide coating is provided in the float bath section 36 or another portion of the float glass facility 30 as described above, and the coating devices 62, 64 utilized to form a non-doped tin oxide coating. It can be formed directly on or above the non-doped tin oxide coating utilizing another coating device 64-68 located downstream of. In another embodiment, the coating device 66 may be provided and may be utilized to form a coating containing fluorine-doped tin oxide. In this embodiment, the silicon oxide coating can be formed directly on or above the doped tin oxide coating utilizing a coating device 68 located downstream of the coating device 66.

A suitable non-oxidizing atmosphere, generally nitrogen, or a nitrogen-hydrogen mixture predominantly nitrogen, is maintained within the float bath section 36 to prevent oxidation of the molten tin 46 constituting the float bath. Atmospheric gas is introduced through a conduit 70 operably coupled to the distribution manifold 72. The non-oxidizing gas is introduced at a speed sufficient to compensate for the normal loss, and to prevent the ingress of outside air, a slight positive pressure about 0.001 to about 0.01 atm higher than the ambient atmospheric pressure is applied. maintain. For the purposes of explaining the present invention, the above pressure range is considered to constitute normal atmospheric pressure.

Preferably, the silicon oxide coating is essentially formed at atmospheric pressure. Thus, the pressure in the float bath section 36, the glass annealing furnace 40, and / or the gap 60 between the float bath section 36 and the glass annealing furnace 40 can be essentially atmospheric pressure.

The heat for maintaining the desired temperature range within the float bath section 36 and the enclosure 54 is provided by the radiant heater 74 within the enclosure 54. Since the cooling section 42 is not enclosed, the atmosphere in the glass annealing furnace 40 is typically the atmosphere, thus the glass ribbon 38 is open to the ambient atmosphere. Subsequently, the glass ribbon 38 is cooled to the ambient temperature. To cool the glass ribbon 38, ambient air can be directed against the glass ribbon 38 by a fan 76 in the cooling section 42. A heater (not shown) may also be provided in the glass annealing furnace 40 to gradually reduce the temperature of the glass ribbon 38 according to a predetermined region as the glass ribbon 38 is conveyed through it.

Tables 1-3 are provided below to show the advantages of certain examples of CVD processes. In Table 1, examples within the scope of the present invention are Examples 1 to 4. In Table 2, examples within the scope of the present invention are Examples 5 to 28. Comparative examples that are not considered part of the present invention are designated as Comparative Example 1 in Table 2. In Table 3, examples within the scope of the present invention are Examples 29 to 46. In the description of the embodiments of Examples 1 to 46, the silicon oxide coating may be designated in the table and below as SiO ₂ : X, where X is phosphorus, boron, or phosphorus and boron. Is. However, it should be understood that Examples 1-46 are for purposes of illustration only and should not be construed as a limitation to the present invention.

The following experimental conditions are applicable to Examples 1 to 4.

The coated glass articles of Examples 1 to 4 have a glass / SnO ₂ / SiO ₂ / SnO ₂ : F / SiO ₂ : X arrangement. The glass substrate was of the soda lime silica type and was moving at a line speed of 3.81 m / min when the coating layer was deposited on the glass substrate. Prior to forming the silicon oxide coating, a pyrolytic tin oxide (SnO ₂ ) coating was deposited on a glass substrate. After forming the tin oxide coating, a pyrolytic silica (SiO ₂ ) coating was deposited on the tin oxide coating. A pyrolytic fluorine-doped tin oxide (SnO ₂ : F) coating was deposited on the silica coating. After forming the fluorine-doped tin oxide coating, a pyrolytic silicon oxide (SiO ₂ : X) coating was deposited on the doped tin oxide coating.

The silicon oxide coatings of Examples 1 to 4 were deposited by forming a gas mixture. In Example 1, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), water (H ₂ O) steam, ethylene (C ₂ H ₄ ), triethyl phosphite (TEP), and inert. It contained gas. In Examples 2 to 4, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), water (H ₂ O) steam, ethylene (C ₂ H ₄ ), triethyl phosphite (TEP). , Triethylborane (TEB), and an inert gas. In each of Examples 1 to 4, the precursor molecules were mixed to form a gas mixture, which was then fed through a coating apparatus before being oriented towards and along the glass substrate. .. The mole percent of the individual gas precursor molecules of Examples 1 to 4 is as shown in Table 1. The rest of the gas mixture of Examples 1 to 4 was composed of an inert gas.

In Table 1, the thickness of the silicon oxide coating is reported in nanometers.

The composition of each of the silicon oxide coatings of Examples 1 to 4 was analyzed using secondary ion mass spectrometry (SIMS). The amount of phosphorus relative to silicon in the silicon oxide coatings of Examples 1 to 4 was similar. The amount of boron relative to silicon in the silicon oxide coatings of Examples 1 to 4 increased from Example 2 to Example 4. Boron was not detected for the silicon oxide coating of Example 1 because the boron-containing compound was not used to form the silicon oxide coating of Example 1.

Referring here to Table 2, the following experimental conditions are applicable to Comparative Example 1 and Examples 5-5. The coated glass article of Comparative Example 1 has a glass / SnO ₂ / SiO ₂ / SnO ₂ : F / SiO ₂ arrangement, and the coated glass articles of Examples 5 to 28 are glass / SnO. ₂ / SiO ₂ / SnO ₂ : F / SiO ₂ : X arrangement. The glass substrate was of the soda lime silica type and was moving at a line speed of 3.81 m / min when the coating layer was deposited on the glass substrate.

In Comparative Example 1, a pyrolytic tin oxide (SnO ₂ ) coating was deposited on a glass substrate. After forming the tin oxide coating, a pyrolytic silica (SiO ₂ ) coating was deposited on the tin oxide coating. A pyrolytic fluorine-doped tin oxide (SnO ₂ : F) coating was deposited on the silica coating. After forming the fluorine-doped tin oxide coating, a second pyrolytic silica (SiO ₂ ) coating was deposited. In Examples 5 to 28, a pyrolytic tin oxide (SnO ₂ ) coating was deposited on a glass substrate before forming the silicon oxide coating. After forming the tin oxide coating, a pyrolytic silica (SiO ₂ ) coating was deposited on the tin oxide coating. A pyrolytic fluorine-doped tin oxide (SnO ₂ : F) coating was deposited on the silica coating. After forming the fluorine-doped tin oxide coating, a pyrolytic silicon oxide (SiO ₂ : X) coating was deposited on the doped tin oxide coating.

The silicon oxide coatings of Examples 5 to 28 were deposited by forming a gas mixture. In Examples 5-9, the gas mixture comprises monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), triethyl phosphate (TEP), and an inert gas. There was. In Examples 10 to 13, the gas mixture contained monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), triethylborane (TEB), and an inert gas. In Examples 14-17, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), triethyl phosphate (TEP), triethylborane (TEB), and It contained an inert gas.

In Examples 18 to 22, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), water (H ₂ O) steam, triethyl phosphite (TEP). , And an inert gas. In Examples 23-28, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), water (H ₂₀ ) vapor, triethyl phosphite (TEP). , Triethylborane (TEB), and an inert gas.

In each of Examples 5 to 28, precursor molecules were mixed to form a gas mixture, which was then fed through a coating apparatus before being oriented towards and along the glass substrate. .. The mole percent of the individual gas precursor molecules of Examples 5-5 are as shown in Table 2. The rest of the gas mixture of Examples 5 to 28 was composed of an inert gas.

In Table 2, the thickness of the silicon oxide coating is reported in nanometers.

As shown in Examples 5 to 28, the CVD process provides an improved process over the comparative deposition process shown in Comparative Example 1. For example, as shown in Examples 5-5 and Comparative Sedimentation Process Comparative Example 1, if the mol% of the silane compound is equal in the gas precursor mixture, it is provided by the process of Examples 5-5. The thickness of the silicon oxide coating was greater than the thickness of the coating provided by the comparative deposition process Comparative Example 1.

As shown in Examples 5-5 and 18-22, the thickness of the silicon oxide coating decreased as the mol% of the phosphorus-containing compound in the gas mixture increased. In contrast, as shown in Examples 10-10, as the mol% of the boron-containing compound in the gas mixture increased, the thickness of the silicon oxide coating increased. Further, as can be observed in Examples 18-22, if the molar% ratios of SiH ₄ , O ₂ and C ₂ H ₄ are maintained relatively equal, for example in a ratio of 1: 4: 6. The addition of water vapor to the gas mixture generally results in an increase in the thickness of the silicon oxide coating and thus an improvement in deposition rate. Examples 23-28 further show the effect of utilizing water vapor, phosphorus-containing compounds, and boron-containing compounds in the gas mixture. As shown in these embodiments, when water vapor is used in a gas mixture with a phosphorus-containing compound such as TEP and a boron-containing compound such as TEB, the thickness of the silicon oxide coating and thus oxidation. The deposition rate of the silicon coating is generally higher than in embodiments such as Examples 14-17 where only phosphorus-containing and boron-containing compounds are utilized.

Referring here to Table 3, the following experimental conditions are applicable to Examples 29-46. The coated glass articles of Examples 29 to 46 have a glass SiO ₂ / SnO ₂ : F / SiO ₂ : X arrangement. The glass substrate is of the type of soda lime silica formed in conjunction with the float glass manufacturing process and moves at a line speed of 7.57 m / min when the coating layer is deposited in the heating zone of the float glass manufacturing process. Was.

In Examples 29-46, a pyrolytic silica (SiO ₂ ) coating was deposited on a glass substrate before forming the silicon oxide coating. A pyrolytic fluorine-doped tin oxide (SnO ₂ : F) coating was deposited on the silica coating. After forming the fluorine-doped tin oxide coating, a pyrolytic silicon oxide (SiO ₂ : X) coating was deposited on the doped tin oxide coating.

The silicon oxide coatings of Examples 29-46 were deposited by forming a gas mixture. In Examples 29-31, the gas mixture contained monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), triethylborane (TEB), and an inert gas. In Examples 32 to 37, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), triethyl phosphate (TEP), triethylborane (TEB), and It contained an inert gas. In Examples 38 to 43, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), water (H ₂₀ ) vapor, triethyl phosphite (TEP). , Triethylborane (TEB), and an inert gas. In the case of Examples 44 to 46, the gas mixture is monosilane (SiH ₄ ), molecular oxygen (O ₂ ), ethylene (C ₂ H ₄ ), water (H ₂ O) steam, triethyl phosphite (TEP). ), And contained an inert gas.

In each of Examples 29-46, precursor molecules were mixed to form a gas mixture, which was then fed through a coating apparatus before being oriented towards and along the glass substrate. .. The mole percent of the individual gas precursor molecules of Examples 29-46 are as shown in Table 3. The rest of the gas mixture of Examples 29-46 was composed of an inert gas.

In Table 3, the thickness of the silicon oxide coating is reported in nanometers. In addition, the deposition rates of the silicon oxide coatings of Examples 29-46 are reported. In Table 3, the deposition rate is represented in two ways:
(1) Dynamic Deposition Rate (DDR) equal to the value obtained by multiplying the thickness of the silicon oxide coating in nm units by the line speed in m / min units, and is expressed in nm * m / min. To. DDR is useful for comparing coating deposition rates at various line rates.

(2) Concentration adjustment-Dynamic deposition rate (CA-DDR) is equal to DDR divided by the concentration of silane available in the precursor mixture (% SiH ₄ ). CA-DDR is represented by (nm * m / min) /% SiH ₄ and has different precursor concentrations at different line rates, in this case useful for comparing the deposition rates of silicon oxide coatings. ..

As shown in Table 3, Examples 32 to 37 bring the mol% of the phosphorus-containing compound closer to the mol% of the boron-containing compound in the gas mixture utilized to form the silicon oxide coating. It suggests that an increase in the thickness and deposition rate of the silicon oxide coating can be achieved. Furthermore, as can be observed by comparing Examples 38-46 with Example 29-37, the addition of water vapor to the gas mixture is generally of the thickness and deposition rate of the silicon oxide coating. Bring an increase. Examples 38-43 further show the effect of utilizing water vapor, phosphorus-containing compounds, and boron-containing compounds in the gas mixture. As shown in Examples 38-40, when water vapor is used in a gas mixture with a phosphorus-containing compound such as TEP and a boron-containing compound such as TEB, the thickness of the silicon oxide coating and The deposition rate generally increases as the mol% of the boron-containing compound in the gas mixture increases. Also, as shown in Examples 44-46, increasing the mol% of the phosphorus-containing compound in the gas mixture increased the thickness and deposition rate of the silicon oxide coating. In contrast, as shown in Examples 29-31, where water vapor is not contained in the gas mixture, increasing the mol% of the boron-containing compound in the gas mixture increases the thickness and deposition rate of the silicon oxide coating. Diminished.

The above description is considered to be merely an example of the principle of the present invention. Moreover, it is not desirable to limit the invention to the exact structures and processes set forth and described herein, as numerous modifications and modifications will be readily made to those skilled in the art. Therefore, all suitable modifications and equivalents can be considered to be within the scope of the present invention.

Claims (27)

A chemical vapor deposition process for forming a silicon oxide coating,
To provide a moving glass substrate and
To form a gas mixture composed of a silane compound, a first oxygen-containing molecule, a radical scavenger, and at least one of a phosphorus-containing compound and a boron-containing compound.
To orient the gas mixture towards and along the glass substrate.
A chemical vapor deposition process comprising reacting the gas mixture on the glass substrate to form a silicon oxide coating on the glass substrate at a deposition rate of 150 nm * m / min or higher. The chemical vapor deposition process according to claim 1, wherein the glass substrate is a glass ribbon in a float glass manufacturing process. The chemical gas according to claim 1, wherein the gas mixture also contains a second oxygen-containing molecule, the first oxygen-containing molecule is molecular oxygen, and the second oxygen-containing molecule is water vapor. Phase deposition process. The chemical gas phase according to claim 1, further comprising providing a coating device and feeding the gas mixture through the coating device prior to forming the silicon oxide coating on the glass substrate. Sedimentation process. The chemical vapor phase deposition process according to claim 1, wherein the gas mixture comprises the phosphorus-containing compound and the boron-containing compound. The chemical vapor deposition process of claim 1, wherein the silicon oxide coating is formed on the deposition surface of the glass substrate that is essentially at atmospheric pressure. The chemical vapor deposition process according to claim 1, wherein the gas mixture comprises the phosphorus-containing compound, the boron-containing compound, and a second oxygen-containing molecule. The chemical vapor deposition process according to claim 1, wherein the gas mixture comprises the phosphorus-containing compound. The chemical vapor deposition process according to claim 1, wherein the gas mixture comprises the boron-containing compound. The chemical vapor deposition process according to claim 1, wherein the silicon oxide coating is formed on a coating previously formed on the glass substrate. The chemical vapor deposition process according to claim 1, wherein the silane compound is monosilane, the first oxygen-containing molecule is molecular oxygen, and the radical scavenger is ethylene. The chemical vapor deposition according to claim 1, wherein when the silicon oxide coating is formed on the glass substrate, the glass substrate has a temperature of 1100 ° F (593 ° C) to 1400 ° F (760 ° C). process. The chemical vapor deposition process according to claim 1, wherein the deposition rate is 175 nm * m / min or more. The chemical vapor deposition process according to claim 1, wherein the silicon oxide coating is thermally decomposable. The chemical vapor phase deposition process according to claim 3, wherein the gas mixture contains more water vapor than molecular oxygen. The chemical vapor deposition process of claim 3, wherein the gas mixture comprises 50% or more water vapor based on mol%. The chemical vapor phase deposition process according to claim 5, wherein the ratio of the boron-containing compound to the phosphorus-containing compound in the gas mixture is 1: 1 or more. The chemical vapor deposition process according to claim 8, wherein the phosphorus-containing compound is an ester. The chemical vapor deposition process of claim 8, wherein the gas mixture comprises less than 0.7 mol% of a phosphorus-containing compound. The chemical vapor deposition process according to claim 8, wherein the ratio of the phosphorus-containing compound to the silane compound in the gas mixture is 1: 100 or more. The chemical vapor deposition process according to claim 9, wherein the boron-containing compound is an ester. The chemical vapor deposition process according to claim 9, wherein the ratio of the boron-containing compound to the silane compound in the gas mixture is 1:10 or more. The chemical vapor deposition process according to claim 13, wherein the deposition rate is 200 nm * m / min or more. The chemical vapor phase deposition process according to claim 17, wherein the ratio of the boron-containing compound to the phosphorus-containing compound in the gas mixture is 2: 1 or more. The chemical vapor deposition process according to claim 18, wherein the phosphorus-containing compound is triethyl phosphite. The chemical vapor deposition process according to claim 20, wherein the ratio of the phosphorus-containing compound to the silane compound is 1: 100 to 1: 1. The chemical vapor deposition process according to claim 21, wherein the boron-containing compound is triethylborane.